Wood preservative oil



o 45 within the following limits: Up to'210 C., not I *etration at thehighest expected *a Patented Apr.2,1 940 I 1 v I 2,195,413

UNITEDSTATES" PATENT orr ce i v woon ra n stivirlvaom I I Jacquelin- E,Harvey, In, Atlanta, Ga.

N'o Drawing. Application- October 22, 1937,-

Serial No. 170,502

2 claims, (01. 134- 185 The invention relates to creosote-coal tar oilthe tars named, hydrogenating the residue to a valuable as awoodpreservative, paving oiLrOofing point such that when blended withthefirst rematerial, waterproofing material and the like. covered light oilthe desired oil will result, it Coal tar alone may be used for woodimpregnaresults in the case of some of the tars that there 5' tion buthas features which are very objectionis an inadmissible percentage offree carbon, coke able in some situations, such as bleeding, darkresidue and/or insolubles in benzo'l. color, and high temperaturesrequired to reduce e To remove a sufficient percentage and no moreviscosity during impregnation. To avoid the dif of said residue, inaccordance with the present ficulty it is the practice to impregnatewood for invention, the percentage of ,said residue in the some useswith a mixtureof creosote and coal hydrogenated material is determined,and also 1 tar. The percentage most used is called an 80--20 theexcesspercentage of the residue. An amount oil i. e., 80% creosote and20%oil. of the "hydrogenated "material which will carry It is an object'of:the invention to provide athe portion of the residue correspondingto said process for producing a creosote-coal tar oil ofexcesspercentage is separated and evaporated to" any desiredpercentages: to produce -an oil of dryness, the distillate iscondensedand blended the desired percentages from coal tar with subwiththe remaining hydrogenated material and stantially volume for volumeconversion: to pro with the light oil first removed, to produce the;duce creosote-coal tar oils having no more resioil of the creosote-coaltar type oil having the due than is permissible under any certain's'peci- I permissible residue and no more. The residue fications: toproduce oils comparable to-creosote 'from the evaporation-to-drynessstep is discoal tar oil of varying precentages from startcarded so faras the process of the invention is ing materials other than coal tar asfor instance f concerned. any tars or residues oftars recovered from,coal, It is possible by theprocedure above described wood or the sap oftrees. By residue inthis deto produce an oil comparablewith an80-20-oil, I scription and in the appended claims-is meanta '7030,;50-50 10-90, or any other percentage J 25 the bottoms remaining from theremoval, as by of creosoteand oil. distillation, of anycommercialfraction from the A feature of the invention has to'do with pavstartingmaterial above named. ing and roofing material by reason of the dis- Bypractice of the present invention a wood covery that hydrogenation ofpitchreduces the preservative may be' produced falling within the rangeof variation of penetration with changes 30 trade specifications atpresent controlling as a of temperature. One type of paving material isSt d a priming oil which'is liquid at atmospherictem- Suchspecifications in force are as-followsr perature when applied to a baseof broken stone, The solution shall be a coal tar product of. I naturalsub-soil, or the like, and becomes'a solid 3.5 which at least 80% shallbe of coal-gas tar or upon fcuring, to provide a waterexcluding diacokeoven tar, and the remainder. shall be rephragm. For this use ahydrogenated pitch may I fined or filtered coal-gas tar or coke-oventar; .if desired'be blendedwith a relatively'small pert s l p y w t thefollowing requ m nts: centage of creosote-either natural or synthet- Itshall not contain o than wa e t ic-- when the normally liquid oilresulting from 40 shall not contain more than 2% ofmatter'intheblendwill cure as usualbut will not so 40 soluble in benzol;the specific gravity of the soreadily become brittle when cold. lutionat 38 C. compared with water at 15.5" C. For as a i 't 1 1-, or t backShall be 1655 than, more 9 and as a stone coating or] for use bypenetration, the distillate, on a water-free basis, "shall beahydrogenated pitch, brought to the desiredpentmospheric more than 5%;up to 235 C., not more than temperature, will be found to not have theusual f he solution shall yield n t m re than low penetrationunderwinter conditions.

coke residue. The specifications above quoted Many consumers of woodpreservatives, such as Set forth for Purpose Of ra o O y-1 creosote,-creosote-coal tar somudn, or the like,

As already stated, the product of applicants in have privatespecifications for the preservative 0 vention may be made to meetthepresent trade they use. 1 My process is so flexible in supplyingspecifications or any changed specifications that any nature of endproducts, that the, following mayfrom time to time be extant. examplesare cited:

When producing an oil of the creosote-coal tar Example 1.- Any of thepitches are hydro- Y type by firststrippingv a light oil from any ofgenated at from 100 500 0., 100-300 atmosscribed in my Patent No.2,082,885, will substan tially meet the specification of the desiredcreosote coal tar solution.

Example 2.In the production of an oil sub-' stantially meeting thespecification of any desired nature of a creosote-coal tar solution,wherein the desired percentageof synthetic creosote is blended withnecessary percentage of natural coal tar to produce the specifications,control over free carbon, coke residue, insoluble in benzol, etc., maybe had by selection of the starting material, that is, (1) thesyntheticcrecsote and (2) the natural coal tar.

Example 3.-'In the production of an oil of the creosote-coal tarsolution type; using coal tar as a starting material, the tar is chargedto a reaction chamber and hydrogenated under temperature of 100-500 0.,100-300 atmospheres partial hydrogen pressure, with or without catalystor catalysts, and for such a time that samples withdrawn indicate thatthe desired oil has been formed, as for instance 8.11011 equal orsimilar to an 8020, 7030, 60-40, -50, etc. creosote-coal tar solution.

Inthe practice of this form of the invention, and when using certaintars for conversion to, say an oil similar to a 50-50, at times it isfound that even though thedesired distillation range has been induced,the free carbon, coke residue and insoluble in benzol are too high;these percentages of mentioned objectionables may be re-' duced asmentioned supra, or the hydrogen partial pressure may be raised, whichhas the effect of reducing said coke residue, etc.

Example 4.-A pitch, as for instance a coal tar pitch, is hydrogenatedunder hydrogenating conditions of 100-500 0., temperature 100300atmospheres partial hydrogen pressure, with or without catalyst or"catalysts, and for such a 'lengthof time that samples withdrawnindicate that when said hydrogenated pitch. is blended with desiredpercentage of synthetic creosote. an oiYcomparableto a creosote-coal tarsolution is formed. By control of hydrogenation of said pitch and/ornature of synthetic creosote and/or 7 percentage of said hydrogenatedpitch'and said synthetic creosote used in said blend to form the oilcomparable to a creosote-coal tar solution, an

oil of any desired specification may be made.

Example 5.The production of a wood impregnant, as for instance of thecreosote-coal tar solution type, wherein synthetic creosote is blendedwith natural pitch to produce an oil highlydesirable as a woodpreservative because of its higher toxic value than a wood preservingoil' of like type made from coal tar under present accepted conventionalmanufacturing conditions. and of comparable boiling range, may becarried out as followsz- A synthetic creosote as described in my PatentNo. 2,082,885, isproduced and blended with the necessary-percentage ofnatural pitch as in Examples 5 and 6, or with coal tar as in Example 2,to form an oil comparable to the creosote-coal tar solution'desired ornatural creosote is blended with the synthetic creoso e as in Example 6below. I

The synthetic creosote as disclosedin my patent referred to has lessthan 10% boiling besamples withdrawn indicate that boiling below suchhigh order as to compensate for-the absence or low value of toxicity insaid pitch.

Example 6.Still another important variation resides in the production ofa wood preservative of the creosote or creosote-coal tar solution typeas follows:

A given coal tar, or the like, is relieved, as by distillation,ofat-least. a portion of its naturally present wood preservative, as forinstance to an upper limit of 300 0. The resultant pitch is thenhydrogenated under conditions, as for instance a temperature, of -5000., hydrogen partial pressure 100-300 atmospheres, with or withoutcatalyst or catalysts, for such a time that said hydrogenated pitch whenblended with the first removed natural wood preservative will give anoil. depending on percentages used, similar to a creosote orcreosote-coal tar solution.

Example 7.-Another important and valuable form of the invention residesin the use of a metallic halid, such as anhydrous aluminum chloride, asa decarbonizing catalyst.

In this instance, but not in the sense of a limitation of other useable'starting materials, dry crude coal tar is charged'to a suitable reactionchamber with from 1 to 10 percent of said metallic halid, as forinstance, aluminum chloride. The contents of said reaction chamber arethen heated to from 100-500 C., while under agitated conditions, andunder self-generated pressure due to said heat, for such length of timethat when heat and agitation have been discontinued, a portion of theoriginal tar charged to said reactor settles into substantially a heavyunderlyingmass which includes the halid, with a thinner and less viscousover-lying layer. This overlying layer may be separated from theentiremass in any desirable manner and used directly without further treatmentor distillation as a wood preservative, or blended with any other knownwood preservative to form a useful product.

The action of the metallic halid has seemingly the effect of subtractingcarbon from a portion of said coaltar, and may bethe cause, directlyor'in'directly, of the thinner-and over-lying layer mentioned. However,there may be reaction entering into the accomplished and noted resultsthatI do not recognize, thus for convenience. I refer to the notedresult as a de-carbonizing efiect.

Instead of using autogenous pressure, as mentioned supra, pressure ofextraneous source may be used, as for instance, hydrogen, any inert gas.or any hydrocarbon gas, with the added benefit in the .case of hydrogenand the hydrocarbon gases, that the hydrogen or hydrogen contentthereof, may under known conditions enter into the reaction for resultsthat are immediately apparent.

' The example of using a metallichalid as a ,de-

carbonizing catalyst, shall in no way be con- ,pitch or tar, boilingless than 10%at 210 and y I strued to limit the ability of said halidto'promote or assist in'the addition of hydrogen.

In the treatment of the heav underlying layer including the halid', thehalidmay be removed frorn which form's'no part of the'present invention,and the heavy massex halid'used for any useful purpose, as for theinstance the production of synthetic creosote in knownvways.

By the word "fnatural tion oi a tar.

I claim:; 1. 'An oil of the. mass by any known means describing acreosote. or a coaltar oil'or other oils as used herein and in theclaims, is meant an oil derivedby disti11athe wood preserving typecomprising a mixtureof from 10% to 90% of syn-; thetic creosote'produced by hydrogenation of not less than 50%v at '355 C. with from 90%to 10%" of coal tar'fractions boiling substantially completely above20050., said mixture boiling less than 10% at 210 0., and not less than40% at 355 C; and havingtoxic properties inexcess .of those ofamixtureoi natural coal tar products of similar physical properties.

..2. An oil of the wood preserving type c'omv 10% to 90% of synbyhydrogenation of prising, a mixture, of from thetic creosote producedpitch or tar, boiling less'than to 10% of coal tar; said'mixture havingtoxic) properties in excess of a'mixture of natural creo- 10% at 210 0.and not less than 50%be1ow'35 5? C.,with from 90% sote and coal tar'withthe same physical prop erties. Y

JACQUELINE. HARVEY, JR.

